Cellular reinforcing structures and their use as core materials of composites is known from WO 98/10919 A2. The reinforcing structures are arranged between covering layers of the respective composite in a sandwich construction, for manufacturing light but nonetheless rigid composites. The reinforcing structures serve as spacers for the covering layers and increase the bending and buckling resistance of the composites. In order to be able to fixedly connect the covering layers of a composite, between which a reinforcing structure is inserted, to each other by means of a joiner, for example by means of an adhesive or synthetic resin, a honeycombed reinforcing structure is used comprising hexagonal material cells and thin bridges which connect them to each other. The joiner penetrates the cavities of the reinforcing structure between the material cells in the region of the bridges, such that at least in the region of the cavities, a material connection to the covering layers is guaranteed. The structuring into material cells and connecting bridges provides the reinforcing structure with a flexibility such as is needed for manufacturing three-dimensionally deformed composites.
However, producing the cavities or other types of material attenuations to the required precision and a desirable efficiency is problematic. Precisely incorporating the material attenuations, for example by means of milling, laser treatment or water jet treatment, is very time-consuming and therefore cost-intensive.